Pietersen said: "I truly didn't mean to cause upset or tension, particularly with important games at stake."

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Rebuilding trust with Pietersen will take a long time - Andrew Strauss

But England managing director Hugh Morris said further talks were needed to see if trust and mutual respect could be regained.

Pietersen, who has cast doubt on his own England future and revealed he had points to "sort out in the dressing room", said in his apology: "The texts were meant as banter between close friends. I need to rein myself in sometimes.

"I did send what you might call provocative texts to my close friends in the SA team.

"I apologise to Straussy [captain Andrew Strauss] and the team for the inappropriate remarks at the press conference and for the texts."

However, the ECB wanted assurances by Sunday afternoon from the 32-year-old batsman that he had not sent derogatory texts about captain Andrew Strauss.

Pietersen did not do so by the deadline and was then dropped from the squad to face the Proteas at Lord's.

Morris said a "successful conclusion to the process was in everyone's best interests".

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Smith - Pietersen situation 'disappointing'

However, he added: "Further discussions need to take place to establish whether it is possible to regain the trust and mutual respect required to ensure all parties are able to focus on playing cricket and to maintain the unity of purpose that has served us so well in recent years.

"Critically, those discussions should take place behind closed doors, rather than in the media spotlight."

It is unclear whether the tensions can be resolved by Saturday when England's 15-man squad for the World Twenty20 in Sri Lanka must be confirmed.

Pietersen, who has 1,176 Twenty20 runs and was player of the tournament when England lifted the trophy in 2010, was not included in the original 30-man party after quitting limited-overs internationals in May. However, he can still be called up to the final squad.

Strauss said it would have been "untenable" to have Pietersen in the squad to face South Africa.

"He is a world-class player and no-one will deny that," he said. "When he is playing well and happy in dressing room he is a great asset, but that's not where we are at the moment. The selectors made a brave and correct decision.

"I'd prefer the issues were resolved in private without media and PR companies and press releases.

"It is a broader issue than just text messages. It is about trust and mutual respect.